The initially light-hearted exchanges are rendered all the more poignant and heart-rending by the fact that the video was captured by a 17-year-old student whose body was later recovered from the submerged ferry, along with his cellphone.

"Hey, rescue me," jokes one male student, while another suggests the video would be "fun to put on Facebook" later.

"It's getting like the Titanic," says another as the 6,825-tonne Sewol begins to list further to one side.

The in-built-timer shows the student, Park Su-Hyeon, began recording at 8:52am on April 16, several minutes before the Sewol crew sent out the first distress signal.

Eleven minutes later, the students are still in a jovial mood, with one joking that it might be time to "leave my last words," and others debating whether the incident might get on the news.

The footage was released to the South Korean media by Park's father, with the footage pixillated to hide the identities of the students.

Throughout, a loudspeaker can be heard telling passengers to remain where they are.

The captain and 14 of his crew who survived the sinking have been arrested and widely criticized for delaying the evacuation order until the ship was listing so sharply that escape was almost impossible.

The captain argued that he was worried passengers jumping overboard before rescue vessels arrived would have been swept away and drowned.

"What is the captain doing?" asks one of the students on the video.

Of the 476 people on board the Sewol, 325 were students from the same high school on an organized trip to the holiday resort island of Jeju.